The feature flag being `single_mr_diff_view`

When the backend for this feature flag was implemented,
everything was stubbed out to be false so it would pass.

The frontend work to integrate it has now flipped that, and all
the stubs should be removed.

This change modifies the actions and mutations
to handle only a single diff style (either inline or
parallel) and properly merge that with existing
files already in state (if any).

Resolve "Add 'immer' library to our dependencies list"

See merge request gitlab-org/gitlab!22869

Revert "Patch Prometheus services records"

See merge request gitlab-org/gitlab!22935

Enable parent/child pipelines

See merge request gitlab-org/gitlab!21830

Use GraphQL to load error tracking detail page content

See merge request gitlab-org/gitlab!22422

REST call is filling up missing fields

Merge branch '118803-transient-failure-in-spec-features-merge_request-user_posts_notes_spec-rb-156' into 'master'

Resolve "Transient failure in spec/features/merge_request/user_posts_notes_spec.rb:156"

Closes #118803

See merge request gitlab-org/gitlab!22951

Merge branch '195670-save-full-dashboard-to-vue-store-so-it-can-be-edited-and-saved-back-to-the-backend' into 'master'

Move entire metrics dashboard to Vuex state

See merge request gitlab-org/gitlab!22722

Code Review Analytics: Add search bar

See merge request gitlab-org/gitlab!22534

Dedupe d3 dependency

See merge request gitlab-org/gitlab!22931

Fix reply emails with attachments for epics

See merge request gitlab-org/gitlab!22547

Fix emails with attachments not creating notes on epics

Clean up discard duplication in IDE

See merge request gitlab-org/gitlab!22572

Add cycle analytics median line data utils

See merge request gitlab-org/gitlab!22802

Utils methods for computing and transforming duration chart
median data have been added here.

* Document what problem it solves
* Add screenshot and examples
* Add references to Parent-child pipelines in docs
* Add reference to YAML keyword index and in the
  pipelines page

Allow CreateCrossProjectPipelineService to create
a pipeline when the same project is provided for
target and source.

Add parent/child pipeline limitations (2nd attempt)

See merge request gitlab-org/gitlab!22675

Resolve "Neaten up tooltip styling on cycle analytics duration chart"

Closes #42677

See merge request gitlab-org/gitlab!22883

Currently only the panel groups are kept in the store
and other dashboard information is discarted.

In order for the information to be preserved by the client
it must be saved to the store.

- Adds the search bar to
the code analytics review page

Do not render label in sidebar when not shown

See merge request gitlab-org/gitlab!22813

This is because of an upgrade in gitlab-ui

Merge branch '30229-background-migration-pruneorphanedgeoevents-did-you-mean-pruneoldeventsworker' into 'master'

Fix: undefined background migration classes for EE-CE downgrade

Closes #30229

See merge request gitlab-org/gitlab!22160

Edit to CI quick start intro

See merge request gitlab-org/gitlab!22814

Restructuring to be more concise

Missing hypen - in Example

See merge request gitlab-org/gitlab!22817

[FE] Visualize Tasks by Type in Customizable Cycle Analytics

See merge request gitlab-org/gitlab!19602

Updated doc related to job concurrency

Closes #193484

See merge request gitlab-org/gitlab!22891

Allow apps to be installed without helm installed if local tiller enabled

See merge request gitlab-org/gitlab!22746

This means we can disregard whether Helm is installed or not

Move specs regarding set_initial_status to
cluster_application_initial_status.rb as not every application has the
common set_initial_status (elasticstack and jupyterhub)

Fix missing CERT_MANAGER_VALUES_FILE var

See merge request gitlab-org/gitlab!22939